1. Field of the Invention
The invention relates generally to yarn tubes and similar articles, particularly such articles which are formed of multiple plies of paper or thin paperboard. The invention is further concerned with improvements in tube identification which are brought about by reverse printing of dyes in varying colors and/or patterns on a ply of the tube.
2. Description of the Prior Art
Yarn tubes formed of multiple plies of spirally wound strips of paper or thin paperboard have long been used as a base member onto which yarn or similar material is wound. Such yarn tubes are formed with a spirally wound outer ply which provides a generally smooth outer surface having surface characteristics which are compatible with the function of the tube, that is, to receive and discharge yarn in the usual applications. The outer surface of a yarn tube must be smooth and free of "fuzz" in order that yarn can readily be transferred to and from the tube. In order to provide desirable surface characteristics, polymer plastic coatings can be formed on the outer paper ply. However, standard practices in the industry now virtually require that yarn tubes be printed with color and pattern markings which identify the material wound on the tube. Tube outer ply papers which are coated on the outer surfaces thereof with polymer plastic coatings cannot economically be printed or marked permanently as the tube is being manufactured.
In order that the advantages of a polymer surface coating can be combined with a desired color or pattern in a manufactured tube, it has become standard practice in the art to use preprinted or predyed paper manufactured by first printing the dye onto a substrate paper and then coating the printed paper with a polymer coating. This practice results in a number of disadvantages, particularly the necessity for obtaining and maintaining large inventories of different colored and patterned coated papers. Coatings on innermost plies are also often necessary in order to protect the tube from wetting and/or to facilitate mounting of the tube on a mandrel. The present invention provides a method and article whereby identification codes or indicia can be applied to a paper ply of a yarn tube as the yarn tube is being manufactured, the identification coloration or pattern thus becoming integral with the tube itself at the time of manufacture and without the need for maintaining large inventories of preprinted papers which are either precoated or coated in-line with a polymer plastic. The article of manufacture produced according to the present method is a tube which is less expensively manufactured but which provides instant information relative to the source, destination and nature of the product which is carried by the tube.